When to use Temperature control valves?

Arthur Binder

We are proposing to install Nexus flow control valves on a boiler/chiller system on duct mounted hot water coils/chiller coils. The instuctions show they can be installed either with or without temperature control valves. Under what circumstances would I have to use a TCV and would the system operate properly without them?

Art Pittaway

There's a difference

between a flow control device and a temp. control valve. The flow control (look up Griswold Controls) has a spring and piston that moves as the pressure differential in a system changes to give a relatively constant rate of flow.(G.P.M.) A temperature control valve will throttle in responce to a temperature controller to limit the heat or cooling output of a air handling device.
The system MAY operate better with the flow control valves but will definitely not function without temperature control valves. Proper system design and pump sizing are the best way to get a system that works properly. It is a bad idea to install them in a system that was not designed for them. The pump and system pressure drop need to be calculated for everything to work properly.

Is this a plan and spec project?
Art